Download 18.1 Electromagnetic Spectrum

Electromagnetic Spectrum
What’s the Wavelength?
E-M Spectrum
http://3enscience.files.wordpress.com/2010/06/em-spectrum21.jpg
Radio Waves
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Relative size: 100’-60 mi
Frequency: low
Amazing Facts
Earth’s Atm:
– bend easily around curve of Earth
– Penetrate dust & gas
• Use
– communication
Radio Waves
• Telescopes
– Arecibo, PR
• What we “see”
– Active galaxies
– Pulsars
– Quasars
– Supernovae remnants
• Wow…cool facts
Microwaves
• Relative size: 1mm - 1 m
• Frequency: 109
• Amazing Facts
• Earth’s Atm
– Pass freely through the air
• Use
– Cell phones
– TV
– cooking
Microwaves
• Telescopes
• What we “see”
– Cosmic background radiation
• Wow…cool facts
Infrared
• Relative size: 1/10 inch (sand grain)
• Frequency
• Amazing Facts
– Warm objects give off IR
• Earth’s Atm
– Absorbed by Earth’s CO2 & H2O in atm.
– Can not be used for communication
• Use
– Heat signature applications
Infrared
• Telescopes:
– Hubble ST
– Keck
– Spitzer
– ISO (Infrared Space Observatory)
• What we “see”
– Young stars with outflowing gases
– planets
• Wow…cool facts
Visible
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Relative size: bacteria
Frequency
Amazing Facts: ROY G. BIV
Earth’s Atm:
– Allows frequency through
• Use
– dah
Visible
• Telescopes
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Twin Keck
Kitt Peak, Tucson AZ
HST
National Optical Astro. Observatory
Optical telescopes
• What we see
– Stars
– sun
• Wow…cool facts
Ultraviolet
• Relative size: virus; atom
• Frequency
• Amazing Facts
– Can kill or disrupt human cell reproduction
• Earth’s Atm
– Ozone absorbs UV
– Can cause sunburn
• Use
– Sterilize medical equipment
Ultraviolet
• Telescopes:
– HST
– SOHO
– EUVE Extreme UV Explorer
• What we “see”
– Hot stars
– Sun’s corona
• Wow…cool facts
X-Ray
• Relative size: atom
• Frequency
• Amazing Facts
– Penetrate through soft materials
• Earth’s Atm
– Absorbed in Earth’s upper atmosphere
• Use
– To “see” through less dense materials
X-rays
• Telescopes:
– Chandra
– ROSAT (Roentgen Satellite)
• What we “see”
– Black holes
– Collapsed stars
– Between galaxies
– Exploded star’s hot gases
• Wow…cool facts
Gamma Rays
• Relative size: nuclei
• Frequency: HIGH
• Amazing Facts
– Pass through most solids
– Most energetic
• Earth’s Atm
– Blocks gamma rays
• Use
– bombs
Gamma Rays
• Telescopes
– Compton Telescope
• What we “see”
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Black holes
Neutron stars
Supernovae
Pulsars
Quasars
Exploding stars
• Wow…cool facts